Monday, November 16, 2020

Tokutanjo Castle -From castles of nation to forts of local power (3)-

Tokutanjo Castle

-From castles of nation to forts of local power (3)-



Name: Tokutanjo Castle (Tokutanjo)
Place: Nishitokutan Yahaba town, Iwate
Type: Flat Castle
Built: 811
Remaining remnants: Clay walls and dry moats 

Brief History

Tokutanjo castle (徳丹城) is located over the flat area between Kitakami-gawa river and current Yahaba town at 15 kilometer southward from Morioka city central. Route 4, an artery of Tohoku region which connects Sendai city and Aomori city runs west half of the ruin thus inner part of the castle existed at the east of the road but west side wall locates opposite of the road.

Tokutanjo castle exists at the edge of low height plateau spreads eastward from Yahaba station. As this plateau is surrounded by wetlands do not need irrigation, this area had been developed for rice cultivation since ancient era, which is shown by ruins of Jomon era and Ezomori old tombs. 

Process of operation at Kitakami basin

Tokutanjo castle was built in 811, under application of Watamaro Funya (765-823), the regional commander of Imperial Household at Kitakami basin. In the end of 8th century, under the command of Tamuramaro Sakanoue (758-811), the predecessor of Watamaro Funya, the Imperial Household army entered into Kitakami basin and built Isawajo castle (Iwate prefecture) in 802 to secure south half of the basin.

Next year Tamuramaro Sakanoue marched to the north half of Kitakami basin and built Shiwajo castle (Iwate prefecture). Shiwajo castle was a huge castle of 840 meter long square, which was equivalent to Tagajo castle (Miyagi prefecture) that was Japanese eastern vice capital at that era. Based on Shiwajo castle, Tamuramaro prepared for next campaign toward north.

However in 805, considering the burden of people, there was a discuss on good government at the cabinet. A minister insisted people suffered from military operation at Tohoku region and construction of Heiankyo capital, then Emperor Kanmu (737-806) accepted this opinion then decided to the suspension of military operation and capital construction.

Build of Tokutanjo castle

After the death of Emperor Kanmu, next Emperor Saga (786-842) , Tamuramaro Sakanoue was appointed as a high rank minister then Watamaro Funya once served to Tamuramaro and was familiar to the situation of Kitakami basin succeeded the role of Tamuramaro Sakanoue. 

In 811, Watamaro Funya started last operation of Imperial Household army at Kitakami basin. Watamaro marched to current Ninohe area and Hei area from Kitakami basin and seized both areas. Watamaro reported the completion of his operation and decrease of troops to the cabinet and was approved.

Considering this situation, Shiwajo castle was too large and expensive only for maintaining securities. Watamaro applied to abolish Shiwajo castle due to the damage by flood and newly build Tokutanjo castle. The flood might be an excuse of abolition of Shiwajo castle considering the fame of Tamuramaro Sakanoue and it might be a restructuring of army and castles.

Structure of Tokutan castle

The size of Tokutanjo castle is about 350 meter long square and less than half of Shiwajo castle. It is a clear square shape but forcibly built over smaller trapezoid shaped plateau, thus southwestern corner and southeastern corner exceeded the edge of plateau and were built at the marsh. 

North line which was on the plateau is securely protected by combination of pressed clay wall and dry moat like Isawajo castle or Shiwajo castle, but other three directions faces the marsh was secured by wooden fences, due to weak ground and decrease of construction costs. Gates were built at the middle of each direction and south gate might be the main gate of the castle.

At the center of the castle, there is a inner area of 80 meter long square which had main hall and two sub halls which might be used for ceremony or meetings. Inner area might be encircled by pressed clay wall and have four gates at each direction. Surrounding inner area there might be administrative offices or storages along with grid street, and because of limited size there was no place for the camp of soldiers like Isawajo castle or Shiwajo castle.

Cease of operation

At the east of central area, there was a remnant of precedent local administrative office. Probably there might be a providential office or river port office before the construction of the castle, and Tokutanjo castle might be built utilizing such precedent office. From this part a canal to Kitakami-gawa river was built, to transport supply and soldiers from the river.

After the completion of Tokutanjo castle, 500 soldiers stationed at Tokutanjo castle for four years, But due to fiscal problem, the post of central troop was abolished both at Tokutanjo castle and Isawa castle in 815. Based on remnants Tokutanjo castle might be used by the middle of 9th century or beginning of 10th century, as an administrative office and base of local troop.

Finally Tokutanjo castle became not used and was abolished, then the remnant was covered by soil and disappeared. As the record of Tokutanjo castle is quite limited and only shows its existence, the location of the castle was a mystery. After World War 2, the remnant of wooden pillars were found by cultivation and development, and as a result of excavation the remnants of fences and gate were found and identified as the remnant of Tokutanjo castle.

Afterward of castle

Now no remnants remain on the terrain but former shape of Tokutanjo castle is gradually revealed by the process of prospection. As the castle was disposed after short term use and covered by soil, items such as wooden helmet, earthenware or stoneware were found and compliments limited literary records of the castle.

Now westward of Route 4 is under the process of park improvement and the location of fences and gates are expressed at the ground. Eastward of Route 4 also shows the location of inner area but not so maintained. The size of Tokutanjo castle is clearly smaller than Isawajo castle or Shiwajo castle and the structure becomes simple, then this shows the end of strong national operation and rise of local powers.


15 minutes drive from Tohoku Jidoshado Expressway Yahaba smart-interchange to parking of Yahaba town history museum. 

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Pictures (click to enlarge)

Saturday, October 31, 2020

Shiwajo Castle -From castles of nation to forts of local power (2)-

Shiwajo Castle

-From castles of nation to forts of local power (2)-



Name: Shiwajo Castle (Shiwajo)
Place: Shimoota Morioka city, Iwate
Type: Flat Castle
Built: 803
Remaining remnants: Clay walls and dry moats 

Brief History

Shiwajo castle (志波城) is located at the center of half-round flat plain spreads at the southward of Shizukuishi-gawa river and at the west of Kitakami-gawa river. Current Morioka city central spreads over the east side of Shizukuishi-gawa river and Kitakami-gawa river, then castle site is at the opposite of two rivers from Morioka city central.

Shizukuishi-gawa river which flows from Ou mountains toward east is used as a communication route toward Yokote basin and Akita basin of current Akita prefecture across the mountains. Beside, abundant melt water wet the fields of the area, but sheer slope of the ground and abundant water also was a cause of severe flood before the construction of Gosho dam.

Castle site is placed over long and narrow slight elevation spreads east and westward along with the direction of Shizukuishi-gawa river. Avoiding the effect of flood, this small elevation has been developed since ancient era, and many old tombs were built in 7th century and 8th century by local residents.

Expansion of Imperial Household into Kitakami basin

In the latter half of 8th century, the power of Imperial Household already reached to the north edge of current Miyagi prefecture from its regional base Tagajo castle (Miyagi prefecture). Further the Imperial Household tried to expand its territory into Kitakami basin, but faced strong resistance of local residents called as “Emishi” and suffered fatal defeat at the battle of Subushi in 789.

Tamuramaro Sakanoue (758-811), a talented general of the Imperial Household, at first served as the vice commander of the expedition held in 794. Later Tamuramaro was appointed as “Seii Taishogun”, a grand general of marginal area which later turned to the name of Shogun, from Emperor Kanmu (737-806) and seized the command of the army at Tohoku region.

After careful preparation for several years, in 801 Tamuramaro Sakanoue entered into Kitakami basin and broke the army of local residents. Tamuramaro once returned to Kyoto city but next year visited Kitakami basin again to build Isawajo castle (Iwate prefecture), a forefront base of Imperial Household at the south part of Kitakami basin .

Construction of Shiwajo castle

During the construction of Isawajo castle, Aterui (?-802) who was the leader of local residents and broke the Imperial Household army at the battle of Subushi surrendered. Tamuramaro Sakanoue took Aterui and his colleague Mori to Kyoto city and recommended to accept the surrender, but the cabinet declined this recommendation and executed Aterui and More.

At the same time, castle site was governed by another leader Anusiko but Anusiko followed to the Imperial Household earlier. Due to stabilization at the south part of Kitakami basin Tamuramaro Sakanoue marched northward to current Morioka city area. In 803, preparing further expansion toward the north edge of Kitakami basin, Emperor Kanmu ordered Tamuramaro to build Shiwajo castle, and Shiwajo castle might be completed at that year.

Shiwajo castle is at the same diameter as Akitajo castle (Akita prefecture), another basement of Imperial Household at the side of Sea of Japan. Both areas are north edge of plain area and worked as the north border of ancient Japan in cooperation. At the north of this line there are flat places such as Hachinohe area, Noshiro area or Tsugaru plain, but direct action were not taken to such areas.

Structure of Shiwajo castle

Basic structure of Shiwajo castle is same as Isawajo castle, which consists of square shaped outer wall and inner area. Outer wall of Shiwajo castle is about 840 meter long square, and two size larger than Isawajo castle that size is about 670 meter long square. Outer wall is built by pressed clay and was about 4.5 meter tall and 2.4 meter wide, which was same as Isawajo castle.

Outside of outer wall there was a dry moat which was about 6 meter wide and 1 meter depth wholly encircled the outer wall. About 60 meter apart, there were watching place of the guardians straddled over the top of clay wall. At the middle of south line, were was a main gate of the castle which was a two story barrack gate of 20 meter width, which is equivalent to the south gate of Isawajo castle.

Inner area is about 150 meter long square area and larger than that of Isawajo castle which was 90 meter long square, and even Tagajo castle that was 120 meter long and 100 meter width and the main place of vice capital of ancient Japan. Inner area had four gates at the middle of each line, but the south gate was a main gate and held a hiding fence at the backside of the gate.

Isawajo castle had one main hall and several barracks, but Shiwajo castle held one main hall and two sub halls, and about 10 barracks in the area. The structure of inner area looks like the one of Tagajo castle or Dazaifu city which were vice capitals of ancient Japan, and the Imperial Household might think Shiwajo castle was equivalent to such castles and substitute the function of Tagajo castle.

Surrounding inner area, remnants of barrack building were found and they might be administrative buildings. At the south of these buildings there were halls to be used for shacks and there might be blacksmiths. Near the outer wall there might be over 1,000 shacks with stove, and they might be a camp of guardians sent to Shiwajo castle.

Abolition from policy change

Being appraised for the stabilization of Kitakami basin and build of Isawajo castle and Shiwajo castle, Tamuramaro Sakanoue promoted to “Sangi”, the member of cabinet. Tamuramaro was appointed as “Seii-Taishogun” again in 804 and prepared for next expedition, but in 805 Emperor Kanmu decided the resume of expedition and construction considering fiscal problem and exhaustion of people.

In 811, Watamaro Funya (765-823) who worked under Tamuramaro Sakanoue made last campaign at Kitakami basin and fixture whole part of Kitakami basin. Watamaro reported the closure of expedition and declined of troops to the Imperial Household, then this policy was accepted. 

As Shiwajo castle was too large and needs preservations costs, Tokutanjo castle (Iwate prefecture) which was about half size of Shiwajo castle was built at backside. Shiwajo castle was abolished and materials were reused for the construction of Tokutanjo castle. For a while a troop stayed at the ruin of Shiwajo castle but retreated, then Shiwajo castle went back to waste land and its north part was broken by the flood of Shizukuishi-gawa river.

Afterward of castle

The ruin of Shiwajo castle was covered by soils and slightly remained outer clay wall was seemed as the military camp of Minamoto clan at the battle of Zenkunen in 11th century. But at the construction of Tohoku Jidoshado Expressway the ruin was found by excavation and specified as the ruin of Shiwajo castle recorded in the history.

All building was lost, but now south gate and outer fences at both side of the gate, fence of inner area and three gates except for north side were reconstructed. As the historical museum park, it shows the shape of magnificent castle of 1,200 years ago, especially for the main street between the south gate of outer area and main gate of inner area.

Huge and thick clay wall built at flat land is different from other Japanese castles and looks like a western or mandarin one. It shows Shiwajo castle was a product of national project, thus it might not be built without strong support of nation and it had to disappear after the policy change of the central government. 


15 minutes drive from Tohoku Jidoshado Expressway Morioka interchange to parking of Shiwajo Ancient Park. 

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Pictures (click to enlarge)